Help betta starting to get sick???

[Gen2387]

So I went to feed my fish this morning and saw that he was a little bloated. This has never happened before and I've had him for a year. It's a small bloat, nothing that I was really concerned about so I skipped his meal this morning. Upon further inspection, I realised that the scalle under his belly and a little bit on the side were a little raised. It's very mild. It's not like those pictures I've seen with bettas that are ''pineconing''... is that how you say it? Anyway, I cleaned his tank today and realised that there was uneaten food at the bottom... which never happens... and I remember this week putting food in the tank and he didn't go for the pellets right away like he always does. So I guess for the week, he's been eating a little less.
What can I do? What could it be. I don't have any pictures but I think the description is accurate.

Housing
What size is your tank? 5gallons
What temperature is your tank? 78
Does your tank have a filter? Yes
Does your tank have an air stone or other type of aeration? No
Is your tank heated? Yes
What tank mates does your betta fish live with? None

Food
What type of food do you feed your betta fish? Pellets
How often do you feed your betta fish? 5 pellets twice a day. (they are small pellets)

Maintenance
How often do you perform a water change? Once a week
What percentage of the water do you change when you perform a water change? 50% with gravel vacuum.
What type of additives do you add to the water when you perform a water change? Conditioner

Water Parameters:
Have you tested your water? If so, what are the following parameters?

Everything is normal. Tested this week.

Symptoms and Treatment
How has your betta fish's appearance changed? Small bloat and a little bit of raised scales but not raised all the way.
How has your betta fish's behavior changed? Eats a little less.
When did you start noticing the symptoms? Today
Have you started treating your fish? If so, how? No... I don't really know what to do.
Does your fish have any history of being ill? Nope. Never.
How old is your fish (approximately)? At least 1.5 year. Got him as an adult.

[Perseusmom]

Hi Gen2387 I really dont know what to tell you except just keep and eye on him and watch for anymore bloating and also the scales to be sure it doesnt get any worse. You might want to watch when you feed him and make sure he eats the pellet and only feed one at a time so you can keep u with how much he is eating and so they dont rot at the bottom of his tank. Good luck maybe someone else will come along soon with a better idea of what might be going on with him.

[Gen2387]

I woke up this morning and he's still bloated, with scales a little raised. I put 1 pellet in the tank, he didn't eat. Should I put him in my hospital tank? I have a 1 gallon for that... If I do, should I put salt? How much... I'm so worried, he's my favorite betta, I have 3 and he was the first I ever adopted and never gets sick...

[sainthogan]

generally people use epsom salt to help with bloating. I don't know the amounts you are supposed to use though.

[laynisample]

It sounds like he might be constipated. Feed him some daphnia if he'll eat it. If not, let him fast. Epsom salt is what I would use, I think the measurements are 1tsp/gallon, but I may be wrong. That's what I use in my tanks. Remember to dissolve it in water before adding it to the tank, and only use it for 10 days maximum.